9 But there is also another meaning that must not be passed over, and which I will declare: let every man choose which he likes best. We keep not back what is suggested to us. For it is the Lord's table, and the minister ought not to defraud the guests, especially when they hunger as you now do, so that your longing is manifest. Prophecy, which is dispensed from the ancient times, has for its object the salvation of all nations. True, Moses was sent to the people of Israel alone, and to that people alone was the law given by him; and the prophets, too, were of that people, and the very distribution of times was marked out according to the same people; whence also the water-pots are said to be “according to the purification of the Jews:” nevertheless, that the prophecy was proclaimed to all other nations also is manifest, forasmuch as Christ was concealed in him in whom all nations are blessed, as it was promised to Abraham by the Lord, saying, “In your seed shall all nations be blessed.” But this was not as yet understood, for as yet the water was not turned into wine.
The prophecy therefore was dispensed to all nations. But that this may appear more agreeably, let us, so far as our time permits, mention certain facts respecting the several ages, as represented respectively by the water-pots.
Source: Tractates on the Gospel of John (New Advent)